Nuclear dreams and nightmares

President Obama's commitment to a "global zero" as the goal of a nuclear-free future could signify the start of an important shift in America's legitimacy in tackling the worldwide nuclear arms race (Reports, 6 April).

By prioritising disarmament alongside non-proliferation, and seeking to ensure the US fulfils its obligations under the nuclear non-proliferation treaty (NPT), Obama could help restore confidence in a treaty which his predecessors have done much to undermine.

In recent years it has proved difficult for the US to legitimately challenge countries for breaches of the NPT while violating the treaty itself. America has consistently refused to reduce its own nuclear arsenal (as required under article VI) as well as developing and deploying new generations of tactical nuclear weapons around the world (in violation of articles I and II).

President Obama's vision is not just built of words but is already backed by some action. He has stopped funding for the development of a replacement nuclear warhead and is pushing the Senate to ratify the comprehensive test ban treaty. Gordon Brown, who has committed Britain to spending £20bn on Trident replacement, should take note.Stefan SimanowitzLondon

President Obama's words on the possibility of a nuclear-weapons-free world could fill us with hope. But his statement was made at the time of the Nato summit and there was no word at all from the meeting about Nato's policies of minimum nuclear deterrence, nuclear sharing and the first use of nuclear weapons. It is the latter, that is obligations to Nato, which, according to successive UK ministers, means that the UK government would use nuclear weapons first. The Nato states must face up to new ways of thinking and stop claiming nuclear weapons are needed for security or "to preserve the peace". Nato should produce a nuclear-weapons-free defence policy in the revised Strategic Concept expected next year at the summit in Portugal.

Let us hope that the UK government can now take the lead in Nato and begin to carry out its NPT obligations, as well as disarm in good faith. It is now crucially important that UK ministers stop iterating empty comments, such as John Hutton did at the weekend, that the UK needs a "minimum nuclear deterrent".Rae Street

North Korea is not the only challenge to Obama's admirable ambition to see a world free of nuclear weapons. Aside from the obvious difficulties of persuading the current nuclear powers to disarm, he will also at some stage have to face up to Israel's nuclear arsenal. With perhaps 250 warheads, it has a significant proportion of the world's total and yet the US has never contradicted Israel's "strategic ambiguity" as to whether it even possesses them or not.

At some point, the US and Israel will have to openly admit the truth - that Israel has nuclear weapons. Iran and others will always feel threatened until that is acknowledged. Without Israel playing its part in a disarmament process, Obama's dream of a world free of nuclear weapons will remain just that, a dream.Dr Stephen LeahYork

The fuss over North Korea's missile launch should be kept in perspective. It was the United States that created the North Korean state in August 1945 by ordering Colonels Dean Rusk and Charles Bonesteel to draw an arbitrary line on a map of the peninsula. This strategic partition divided a nation that had been united under the Yi dynasty for more than five centuries. The missile launch violated several UN security council resolutions, but when did such violations worry a US indifferent to Turkey's posture in Cyprus and Israel's occupation of Palestine? It is true that North Korea opposes IAEA inspections, but when did the US or Israel allow UN inspections of their nuclear facilities? Complaints that North Korea ignores the nuclear non-proliferation treaty are specious. It withdrew as it is entitled to do under article X of the treaty.Geoff SimonsAuthor, Korea: The Search for Sovereignty